1. Field of the Invention
The present invention relates to a structure for providing backlight for a liquid crystal display, which structure has been optimized for uniformity.
2. Description of Related Art
Liquid crystal materials emit no light of their own. They do however reflect and transmit light from external light sources. Liquid Crystal Displays (xe2x80x9cLCDxe2x80x9d) are rapidly becoming the display material of choice for new, high-technology displays.
Accordingly, it is necessary to back light the LCD, which is typically done with fluorescent lamps located directly behind the LCD. When illuminated from behind, a white diffusion sheet between the backlight and the LCD redirects and scatters the light evenly to ensure a uniform display. When light is transmitted through filters, layers of liquid crystal, electrode layers, polymer films, etc., more than eighty percent (80%) of the light is lost.
Fluorescent lights have a limited useful life and become dim over time. However, there is a new type of electrodeless fluorescent lamp available today that has a substantially longer life span than the electrode variety. Such lamps are manufactured and sold by Sylvania under the trade name ICETRON. These lamps are oval in shape and include a coil at each end for excitation thereof In order to get the light intensity needed for many of today""s modem display requirements, it is necessary to employ a large ICETRON lamp. The problem however, is that this lamp takes up a lot of space and would require a very thick display cabinet (i.e., very deep).
Therefore, a need exists for an optimized back lighting arrangement that is small in size (i.e., very thin), one that produces light with ample brightness and one that has a long life span.
Accordingly, a feature of the present invention is the provision of high intensity light source for use as a back light for LCD""S.
Another feature of the present invention is the provision of a light source for use in a trim LCD display panel.
Yet another feature of the present invention is the provision of a light source assembly that evenly distributes bright light across the back surface of an LCD panel.
These and other features, which will become apparent as the invention is described in detail below, are provided by an apparatus that provides back light for liquid crystal displays (xe2x80x9cLCDxe2x80x9d). The apparatus includes an electrodeless lamp disposed in a cabinet for generating light; and a reflector disposed on one side of the electrodeless lamp for directing light from the lamp in the direction of the LCD and a diffuser. The reflector further includes a surface profile that provides a uniform distribution of light intensity into the LCD. The reflector further is adjacent and in close proximity with the lamp in order to provide a minimum depth behind the lamp. An alternate embodiment of the invention includes an IR reflector disposed between the electrodeless lamp and a diffuser, which is located adjacent the LCD screen.
Still other features and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein is shown and described only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive, and what is intended to be protected by Letters Patent is set forth in the appended claims. The present invention will become apparent when taken in conjunction with the following description and attached drawings, wherein like characters indicate like parts, and which drawings form a part of this application.